Temporal smearing possible??

Of greater significance than the frequency content of noise, is the temporal structure, with frequent abrupt changes in the signal amplitude resulting in a more annoying sound than one of more or less constant amplitude. As well as altering the frequency content, there ought to be some way of `smearing' the signal in the time-domain...I guess this amounts to reducing the clarity of the signal (i.e. altering the ratio of direct to reverberant sound). I was wondering about using Helmholtz resonators to achieve this...just a vague thought anyhow. Will come back to it.